HOW POPULATION INCREASES 55 
n the table. If, however, the curve had really har- 
monised with the assumption mentioned, the “logistic 
rates,” also shown in the table, would have been the 
ones experienced. When these are compared with the 
“ actual rates” it is seen that they sensibly differ from 
them. And this difference can be fully explained. 
Year ‘ . 1795 1805 1815 1825 1835 1845 185 
Actual rates . 300 310 286 289 283 307 304 
Logistic rates . 300 298 294 290 284 277 265 
Year . . 1855 1865 1875 1885 1895 1905 1915S 
Actual rates. 304 204 263 227 188 191 139 
Logistic rates 265 254 239 220 201 178 156 
One sees immediately from the above table that the 
steady diminution of the rate of increase, characteristic 
of the logistic rates, does not really characterise the 
actual rates of human increase. Similar examinations 
of the rates of increase for France, for Australia, and 
for other places, also show that the assumption does 
not represent the facts: in other words, human popula- 
tions certainly do not conform to the law of growth 
which the logistic curve expresses, excepting accident- 
ally for a limited period.! 
This result is not a merely academic one. It has 
recently been asserted that the United States can 
carry a population of not more than 200 millions and 
it is not impossible that this view may have political 
consequence. It is evidently already reacting upon 
the national attitude to questions of migration, etc. 
The amazing deduction that the United States can 
never have a greater population than 197-274 millions, 
that it can never have more than 65-2 persons per 
See an article “ The growth of human populations, and the laws 
of their increase,” by G. H. Knibbs, in Mezron, Vol. V, No. 3, 1st 
Dec. 1925. Also * The laws of growth of a population,” Four. Amer. 
Stat. Assoc., Dec. 1926, pp. 381-98, and Mar. 1927, pp. 49~59. 
See also Is there a biological law of human population growth,” by 
A. B. Wolfe, Amer. Quart. Four. Economics, Vol. XLI, Aug. 1927.